Citation
Perez, Kathryn A. (2016) Structural and Biochemical Characterization of Ligand Bound States of the FeMo-Cofactor of Nitrogenase. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/Z9M043DX. https://resolver.caltech.edu/CaltechTHESIS:05262016-050606547
Abstract
Nitrogenase is the only known enzyme capable of nitrogen fixation, the reduction of dinitrogen to ammonia, a metabolically available form of nitrogen. Developing an understanding of the complex mechanism required for biological nitrogen fixation requires that the enzyme be characterized in catalytically relevant states, such as those involving ligand binding and reduction. Nitrogenase catalyzes this reaction through the cyclic interaction of two metalloproteins, the Fe-protein and the MoFe-protein which contain three distinct metalloclusters, in an ATP-hydrolysis dependent electron transfer reaction. The binding and subsequent reduction of substrates requires multiple electrons donated from the Fe-protein to the MoFe-protein, in which the active site is located. In this study, we have structurally characterized the binding of two inhibitors to the FeMo-cofactor, CO and the Se of SeCN-. Both interactions involve the displacement of a single S, and the Se was used as a label to follow the interchange of three S sites within the FeMo-cofactor during catalysis. These finding change any future approaches to characterize the mechanism of biological nitrogen fixation, requiring that structural changes be considered for substrate binding and reduction.
| Item Type: | Thesis (Dissertation (Ph.D.)) | |||||||||
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| Subject Keywords: | Nitrogenase, FeMo-cofactor, carbon monoxide, selenium,selenocyanate, MoFe-protein | |||||||||
| Degree Grantor: | California Institute of Technology | |||||||||
| Division: | Chemistry and Chemical Engineering | |||||||||
| Major Option: | Chemistry | |||||||||
| Thesis Availability: | Public (worldwide access) | |||||||||
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| Defense Date: | 19 April 2016 | |||||||||
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| Record Number: | CaltechTHESIS:05262016-050606547 | |||||||||
| Persistent URL: | https://resolver.caltech.edu/CaltechTHESIS:05262016-050606547 | |||||||||
| DOI: | 10.7907/Z9M043DX | |||||||||
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| Default Usage Policy: | No commercial reproduction, distribution, display or performance rights in this work are provided. | |||||||||
| ID Code: | 9762 | |||||||||
| Collection: | CaltechTHESIS | |||||||||
| Deposited By: | Kathryn Perez | |||||||||
| Deposited On: | 09 Mar 2017 17:54 | |||||||||
| Last Modified: | 04 Oct 2019 00:13 |
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